1. Field of the Invention
The present invention relates to an image processing apparatus, an image processing method, and a transmitting apparatus, and particularly to a technique for performing scaling of image data including a tint image in which concealed characters appearing after scanning of the image are embedded.
2. Description of Related Art
A technique for printing a tint image whose output appearance changes when copied in such a manner that characters such as “COPY” appear on a copied sheet is disclosed in JP2005-136953A, for example. The above-described characters such as “COPY” are called concealed characters, which appear on a copied sheet, but are usually printed such that they cannot be recognized with a casual glance. These concealed characters can be realized, for example, by taking advantage of the reproducibility of an image when copying the image that depends on the difference between the printing resolution and the scanning resolution of a scanner scanning the image. For example, when a background area, which is an area other than the above-described concealed character area, is not reproduced after copying, and only the concealed character area is reproduced after copying, then the above-described concealed characters appear in the copied image.